The ability of communications systems to continue to operate effectively under adverse conditions, though portions of the system may be damaged or destroyed. Note: Various methods may be used to maintain communications services, such as using alternate routing, different transmission media or methods, redundant equipment, and sites and equipment that are radiation hardened.

A collection of individual communications networks, transmission systems, relay stations, tributary stations, and data terminal equipment (DTE) usually capable of interconnection and interoperation to form an integrated whole. Note: The components of a communications system serve a common purpose, are technically compatible, use common procedures, respond to controls, and operate in unison.

The translation of user requirements for the exchange of information into cost-effective and low-risk technical solutions in terms of equipment and subsystems. Note: Communications system engineering encompasses the integration of these parts into a complete entity resulting in a minimum investment for the entire system life cycle required to satisfy the requirements of a majority of users of the communication system.

See survivability.

Theory that is devoted to the probabilistic characteristics of the transmission of data in the presence of noise, and that is used to advance the design, development, and operation of communications systems.

The monitoring of one or more communications lines, frequencies, or channels to obtain information by listening to or receiving all transmissions on them and transmitting and receiving messages as required.

The rear part of the theater of war or theater of operations that contains the lines of communications, theater logistics bases, forward operating bases, and other agencies required for the immediate support and maintenance of the field forces. It extends back to the CONUS base. [JP 1-02]

The specialized field concerned with the use of electronic devices and systems for the acquisition or acceptance, processing, storage, display, analysis, protection, disposition, and transfer of information. Note: C-E includes the wide range of responsibilities and actions relating to (a) electronic devices and systems used in the transfer of ideas and perceptions, (b) electronic sensors and sensory systems used in the acquisition of information devoid of semantic influence, and (c) electronic devices and systems intended to allow friendly forces to operate in hostile environments and to deny to hostile forces the effective use of electromagnetic resources.

See cable TV.

A grouping of users who generate a majority of their traffic in calls to other members of the group. Note: The community of interest may be related to a geographic area or to an administrative organization. Synonym special interest group.